Tuberous Receptors Catalogue Electroreception What The Is Tuberous

Tuberous Receptors

Catalogue Electroreception What The Is Tuberous Receptors Structure of Tuberous Receptors How Do They Work

Electroreception There are two general types of electroreceptor organs in fishes. Ampullary receptors are located in recesses in the skin that are connected to the surface by a canal filled with a conductive gel They are sensitive to electric fields of low frequency (<0. 1 to 25 Hz) and are found in many groups of fishes. Tuberous receptors are located in depressions of the epidermis, are covered with loosely packed epithelial cells , and detect higher frequency electric fields (50 Hz to > 2 k. Hz). They are found in fishes that use electric organs to produce their own electric fields, and are most sensitive to the frequencies produced by the fish’s own electric organ.

Tuberous receptors are responsible for active electrolocation – the detection of an electric field produced by the fish’s own electric organs. Therefore, they are only found in those teleosts that generate an electric organ discharge (EOD), such as the mormyrids, gymnarchids, and mochokid catfishes of Africa and the gymnotoids of South America.

The Structure of Tuberous Receptors Tuberous receptors are located in depressions of the epidermis and are covered with loosely packed epithelial cells, allowing electric current to flow between the cells. There at least eight different types of tuberous organs in different species, but they fall into two main categories ——those that encode timing of the EOD, and those that encode stimulus amplitude (von der Emde 1998). The fish’s EOD frequency causes the tuberous receptor cells and their sensory neurons to generate a rather constant background rate of nerve impulses.

The Structure of Tuberous Receptors There are two types of tuberous receptors. Pulse makers and Burst duration receptors. Pulse makers emit one action potential and code for frequency perception, whereas burst duration receptors emit bursts of action potentials and code for amplitude. Both cell types are triggered by electric signals in the surrounding water and result in a neurotransmitted response, (electric organ discharge movement etc) just like any other sensory feature such as taste or smell.

How Do They Work A fish can detect objects moving into its electric field when those objects cause a change in the field and alter the rate of impulses received by the brain, such as when the fish encounters an object with different conductance than the surrounding water. This probably allows the fish to detect the size and distance of the object, and may also permit discrimination between living and nonliving objects because their different electrical properties would create different distortions of the electric field.

Electric fields from other fish are generated regardless of a whether or not they are electrogenic. The use of any muscle creates an electric field, so the contractions of a heart could be detected in another fish. The eels can locate objects accurately by measuring frequencies and amplitudes on different parts of the body as well as static electricity caused by flow of water against the bottom of the river. By using its own electric organ discharge (EOD) and sensing differences in the current around itself, the eel is able to deduce the conductivity of any surrounding objects, another way of navigation and obstacle detection. In addition the EOD from other electrogenic fish can be used for communication

When swimming, the eel minimizes undulating movement by use of its long anal fin, so as to avoid disturbance of its own EOD. It also has the ability to swim backwards. if scanning potential prey, it will start scanning tail end first and finish with its head at the “right end“ of the prey, it will then stun the prey.

Active electroreception is used in a variety of ways. Many electric fishes are primarily nocturnal and use their electrosensory capabilities to locate hiding places during the day and to explore their environment at night (von der Ende 1998; Graff et al. 2004). Active electroreception also can be used to locate prey and assist with navigation and orientation, especially because the fish are most active during periods of low or no light. But the most studied use of active electroreception is in communication.

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